High Availability and Scaling Flashcards
TRUE or FALSE?
Launch configurations support versioning.
FALSE
They are immutable.
Only launch templates support versioning
TRUE or FALSE?
Launch templates can be used to configure all autoscaling features.
TRUE
It’s launch configurations that only support some.
What are 4 things you can specify in a launch template?
- AMI
- Instance type
- Security group
- Networking info
What are the three autoscaling restriction settings?
Minumum, maximum, desired.
What’s one example for when would you use a scaling-out lifecycle hook?
For installing software.
i.e. you don’t want the instance to be in service before the software is properly installed.
What’s one example for when would you use a scaling-in lifecycle hook?
For capturing application logs.
i.e. so they are not lost when the instance shuts down.
What is a lifecycle hook?
A feature that allows you to put instances into a wait state, allowing you to perform tasks before the instance is put into service or before it is fully terminated.
TRUE or FALSE?
The autoscaling group config contains the VPC and subnets where the instances will live.
TRUE
What’s the difference between simple scaling and step scaling?
Step scaling provides more granular control.
It allows you to define multiple actions to take based on a range of metric values, rather than a single threshold.
What could happen if you don’t have a warm-up period in place?
You would get high instance churn, as instances are not ready, fail the health check, and get terminated.
What does a CoolDown period do?
It pauses autoscaling for a certain amount of time, to give the system time to adjust.
Helps prevent runaway scaling events.
TRUE or FALSE?
You can use Reserved Instances as the minimum count in an autoscaling group to save money.
TRUE
If an exam questions mentions an RDS database solution but with unpredictable workloads, think of…
Aurora Serverless
TRUE or FALSE?
RDS storage only scales up, not down.
TRUE
In the exam, a viable scaling option for a relational database is refactoring and…
changing to DynamoDB
TRUE or FALSE?
Standby RDS instances can be used for reads.
FALSE
What are the two scaling options for DynamoDB?
Provisioned and On-Demand
What is the most cost-effective scaling option for DynamoDB?
Provisioned
What is the best scaling option for DynamoDB with an unpredictable workload?
On-Demand
TRUE or FALSE?
With DynamoDB, you cannot switch between scaling options.
FALSE
You can, but only twice per 24 hours per table
If EC2 instances in an autoscaling group are taking too long to provision, consider using…
Baked AMIs
TRUE or FALSE?
Baked AMIs are better than using user data.
TRUE
For questions that ask for a highly available solution for a legacy resource where there is only one instance, think of…
Steady state groups
i.e. the min, max, and desired are all set to 1
To make sure EC2 instances in an autoscaling group are terminated and replaced when unhealthy, be sure to enable…
health checks on the load balancer.
What are the four different types of disaster recovery strategies?
- Backup and Restore
- Pilot Light
- Warm Standby
- Active/Active Failover
What is the default CoolDown period of an autoscaling policy?
300 seconds
